Full circle retreader



in the rubber cover 1 and extending all around the saine, are the electrical heating wires 5, the arrangement of which is lloest indicated in Fig. 5. These heating wires are laid up in parallel convolutions extending across the tread or peripheral portion of the cover 1, and over the channel which receives the gum tread 4L. 'lhe current flow through these resistance wires is thermostatically controlled, so as to maintain a uniform temperature completely across and around the peripheral cover. The thermostat which l -employ is preferably that described and claimed in my copending application Serial No. 530,658, filed April 16, 19.31, but may be of any other Isuitable form which'will meet my present requirements. ln thek diagram of Fig. 4,1 `have' indicated the bottom yof the thermostatl as being in close proximity -tov rnbber. A uniform effect completely around the tread 4is thus maintained within a very fewdeigrees Fahrenheit. l

v6 indicates the tire casing, which in Fig.. 3 is shown with plain or straight sided flanges .and in Fig. 2 shown with clincherflanges. 7 is Vthe inner tube which is inflated to create the requiredpressure. 10 in Fig. 2 indicates smooth metal :rings to insure ready slip of Ythe binding vover the bead of the casing G as the tube 7 is inflated. 8 in Fig.. Q'is .a metal ring to support the walls of thev casing and to prevent the tube 7 from pinching under the .beadjas it would if the ring did not-extend down some distance to the point i9 on each side. 11 indicates the layers of bindingwhich holds the retreader in place.

`Referring to Fig. 3, instead ofthe clincher beads or flanges on the casing 6, and the slip rings 10, in :this modification l use a metal f ning .1'2 uponlwhic'h the tire ismounted, and

tec-tion. The casing 6 and the inner .tube 7 -With .ftheother parts 'broken away in Fig. 3 are supposed to be the same as those in the upper part of Fig. 2,' the only substantial jdiflierence'between these two forms being in the casingfbea'ds or flanges, and the rim parts for .receiving and holding them.

If it should be desired, the rubber matrix 3 may be provided with any desirable tread design to be pressed into and thereby transferred to the new tread 4.

The rubber matrix 3 may be replaced by a metal matrix consisting of short segments hinged to one another and extending all around the inside v'of the cover 1. This metal matrix would rest against the inside face of the rubber cover 1, or against a rubber or fabric layer containing the heating element.

It will be understood that a number of changes and modifications can be made in nonessential details of this design, both in regard to themethod and the apparatus, Without departing from the scope and purview-'of my invention. Thus., the tread cover or matrix 1, which is of rubber, may be made of any other suitable material, and may be formed in vone continuous integral ring to be stretched` over the outside of the casing '6 or it may be made with an Aopening at'one point, in which-case, :the ends should overlap. I consider the continuous ring form preferable, as shown in Fig. 4;. l wish it clearly understood that I contemplate all suc-h non-essential changes :and modifications as fall fairly within the scope of the appended claims. v llVhat l Aclaim is: 1

. A1. The method of retreading a pneumatic tire casing which comprises the following steps: applying anew tread of uncured 'gum completely around the periphery of the casing; covering the .same `continuously .around the periphery, applying pneumatic pressure continuously around the inside of the casing, Kopposing the same with pneumatic pressure separnately applied tosaidcovering-and apply- 4heat :across the tread uniformly through- 'ontthe entire periphery of the same. i i

2. A full circle retreader for pneumatic tire casings comprising the following in-strumen- .tali-ties: lan external ycovering containing a tread inold :and adapted to extend completely around and entirely cover the periphery of the easing, heating means within the substance `of said cover extending ac-ross andaroundfsai-d mold, :and means for expanding `the tire casing within the cover so as to force the gum tread into said mold, together with separate means for tightening said cover in opposition to the Iexp'an'si on 'of the tire casing therein.

3. full circle retreader for pneumatic .tire casings comprisingthe following instrumenltalities: an external covering containing :a tread in old :and adapted to extend completely around and entirely cover the *periphery of the casing, heating means within the .substance of lsaid coverextending completely across and around the entire surface of said mold, and means for expanding 'thetire :casing within the'cover so as to force the gum tread into said mold, said heatingmean's consisting lof electrical resistancewires laid in parallel fconvolu'tions crossing the said mold 

